The 23-year-old from Vancouver will face the No. 1-ranked Novak Djokovic in Friday's opening singles match at the Kombank Arena.
With Pospisil also playing doubles, getting his toughest match out of the way gives him time to rest before teaming up with veteran Daniel Nestor on Saturday in doubles.
"Obviously I don't have to talk about how good of a player (Djokovic) is so I know I'm going to have a tough day on Friday," Pospisil said after Thursday's draw. "I'm happy that I'm playing first and to rest for the doubles on Saturday."
Djokovic only arrived Wednesday night after losing a gruelling four-set match to Rafael Nadal in the U.S. Open final on Monday. There was a concern that Djokovic may be rested Friday and saved for Sunday's much-anticipated match against top-ranked Canadian Milos Raonic.
Djokovic assured the large gathering of Serbian media Thursday he will be ready to go when the best-of-five tie kicks off Friday.
"It's not the first time that I have two days time to get ready," said Djokovic. "It's obvious that I'm tired because I've had a long hard-court season and jetlag and time changes can play a factor to my adjusting to the conditions but I feel quite healthy and very much motivated and inspired to play for my country."
The 11th-ranked Raonic will play Janko Tipsarevic in the second match Friday. The player from Thornhill, Ont., has won all three previous meetings with Tipsarevic but all those wins have come on hard court surfaces. They'll be playing on clay indoors in Belgrade, a surface that has challenged Raonic in the past.
"I'm playing much better on clay and even here after the summer I've had, I have a lot of confidence ...," said Raonic. "Even though it's a bit faster than a traditional clay court and clay court atmosphere, it's something I feel very comfortable with and I feel like I've done well with."
Canada, which upset Spain and Italy in Vancouver to advance, has never played in the Davis Cup semifinals before. Serbia, meanwhile, is trying to get back to the final after winning the event in 2010. The winner of the tie will play the winner of the other semifinal between the Czech Republic and Argentina in November.
Despite being in uncharted territory, the Canadians seemed relaxed Thursday. Raonic and Pospisil warmed up by throwing a football around and kicking a soccer ball over the net before a vigorous training session.
Nestor arrived later with the rest of the staff for a final game of soccer tennis before the team marched in for the draw.
The Canadian team has a strong connection to the Balkan region with Nestor returning to his birthplace while Raonic was born in what is now Montenegro. Frank Dancevic of Niagara Falls, Ont., who saw action in the first round against Spain in February, has a Serbian-born father and has trained in Belgrade recently.
While those connections may earn the Canadians some respect from the 15,000 fans each day, Nestor knows they won't get much support.
"If things get close, and we expect them to, I think for sure they're going to forget about that pretty quickly," Nestor said. "At the end of the day it's about winning the tie so they're going to do what it takes to do that."
In the doubles on Saturday, Nestor and Pospisil will be taking on Ilija Bozoljac and Nenad Zimonic. Bozoljac is a last-second change, replacing Dusan Lajovic.
Nestor and Zimonic were partners between 2008 and 2010. The pair won three Grand Slam titles together so they know each other well. Nestor is more concerned with Lajovic.
"I think Bozoljac brings something new to the table and we have to be prepared for him," said Nestor. "He's a big hitter and a shot-maker and we have to try and take him off his game."
The singles draws are flipped for Sunday with Djokovic opening the day against Raonic and Tipsarevic playing Pospisil.